SimpleBezier

From MHCGraphics

; Mead example file -- some objects built with Bezier curves
;
; Jim Teresco
; Computer Science 110
; Mount Holyoke College
;
; $Id: SimpleBezier.scm 612 2008-04-06 01:19:20Z terescoj $
;
(require (lib "Defs.ss" "Mead"))

; We define an outline polygon like others we have seen for
; Prism, Lathe, extrude, sweep operations.
; The main oddity here is that the point (75 0) is repeated.
; For the operations we have seen previously, this repeated
; point will have no effect, but when specifying Bezier curves,
; we need to specify points in groups of 4, and if they are to
; be connected, the 4th point of one group must match the 1st
; of the next group.
(define outline
  (2to3d '((0 0) (25 100) (50 25) (75 0)
           (75 0) (50 -25) (25 -100) (0 0))))

; we can build a Prism from this outline
(object spikyPrism Prism
        (profile outline)
        )

; but we can also create a Prism and send it an additional
; message to indicate that the outline should be treated as
; a sequence of points defining Bezier curves.
(object roundedPrism Prism
        (profile outline)
        (bezier)
        )

; same outline, but a Lathe this time
(object spikyLathe Lathe
        (profile outline)
       )

; and a Bezier version of the Lathe
(object roundedLathe Lathe
        (profile outline)
        (bezier)
       )

; let's build a Lathe with a single Bezier curve with
; endpoints on the y-axis
(define outline2
  (2to3d '((0 0) (25 25) (200 75) (0 100))))

(object latheObject Lathe
        (profile outline2)
        (bezier)
        )

; add one of each to the scene
(tell scene
      (add spikyPrism redPlaster
           (translate 100 100 0)
         )
      (add roundedPrism redPlaster
           (translate -100 100 0)
           )
      (add spikyLathe redPlaster
           (translate 100 -150 0)
           )
      (add roundedLathe redPlaster
           (translate -100 -150 0)
           )
      (add latheObject redPlaster
           (translate -250 0 0)
           )
      )

(tell image
      (background white)
      (width 1024)
      )

(tell camera
      (pos '(0 300 -500))
      (angle 70)
      (shoot)
      (pos '(0 -100 -500))
      (shoot)
      )